Ever since the attack on the USS Cole in 2000, the threat posed by Fast Inshore Attack Craft (FIAC) has been a central theme for western naval officers responsible for ship defense. The FIAC threat is often referred to as an “asymmetric threat,” meaning that a swarm of small boats operated by a fanatical foe may overwhelm a major warship, much like a swarm of bees attacking a larger animal.
To be able to conduct threat representative live fire naval exercises, expendable kill targets that may be remotely operated have been developed. These expendable kill vehicles may be used to simulate a FIAC attack. One such expendable kill target is the unmanned vehicle known as the Hammerhead, which is designed and manufactured by Meggitt Training Systems. Hammerheads may be remotely operated and used to simulate a FIAC attack.
In one example of a FIAC simulated attack training exercise, one or more expendable kill targets may be remotely operated and directed towards the vehicle in training such as a warship. The warship tries to acquire and destroy the swarming expendable kill targets using live ammunition in a live fire training exercise. If one of the expendable kill targets can penetrate the defenses of the warship and strike the ship before being destroyed itself, then the warship has failed the training exercise. On the other hand, if all of the expendable kill targets are destroyed before any can strike the warship, then the warship has successfully completed the training exercise.
While in an ideal training exercise the expendable kill vehicle would actually try and strike the warship, current methods of training forbid the expendable kill vehicle from striking the warship for safety reasons. In current training methods, one of the major operating safety constraints of live fire exercises with unmanned vehicle targets is ensuring that the target does not strike one of the participating units. In the case of the Canadian and US Navy, there have been several instances of targets striking ships.
Although trying to strike and/or actually striking the ship would increase the reality of the training exercise, current methods forbid strikes for a number or reasons. Strikes to a ship typically happen in one of the most expensive areas to repair, the waterline. Repairing a hole at the waterline necessitates going into dry dock, which itself requires the de-ammunitioning and de-fueling of a warship. These two activities alone may cost over a million dollars in time and effort. In the case of the US Navy, this has led to proscriptive regulations that preclude bringing the target closer than 500 yards from the firing ship. This is known in navy parlance as “the bubble.”
One method of making sure that the unmanned vehicles observe the bubble is to program them to cut engine power, either with software or hardware or both once they breach the bubble. However, even with both software and hardware pre-programmed cut-offs, the bubble still needs to be overly large to protect against “rogue drones.” Rogue drones are unmanned vehicles that no longer respond to software or hardware commands. Because in many training exercises live fire may be used, the unmanned vehicles may suffer damage to the cut-off circuitry and may become unresponsive to cut-off instructions. Rogue drones pose a serious impact threat to participating vessels and therefore, the bubble must be made excessively large. Even with a large bubble, a software or hardware cut-off is not a fool proof solution to the impact problem.
Another problem with the bubble is that it creates a limit to the realism that may be achieved in the training exercises. Studies have shown that the average kill range of a Hammerhead has been less than 150 yards. In order to reduce the risk of impacts with participating vessels, the bubble has been established at as much as 500 yards. This creates an unrealistic training scenario for a number of reasons.
When the unmanned vehicles are farther from the vehicle in training, the ammunition has a longer flight time and thus, the erratic maneuvers of an agile unmanned vehicle make it more difficult to hit. Consequently, elimination of the threat of the unmanned vehicle is more likely to happen within a close proximity to the ship.
A bubble around the vehicle in training causes the unmanned vehicles to either significantly slow down or turn parallel to the vehicle in training when approaching. Slowing down and turning parallel to the vehicle in training at such close range makes the unmanned vehicle easier to target and drastically reduces the realism of the training methods
The data obtained from training exercises gains in usefulness as the training exercise gains in realism. Data from training exercises may actually be harmful if the training exercise is not realistic enough because the data may give a false sense of security. Accordingly, when testing defense systems against the threat posed by unmanned vehicles, it is important that the test be as realistic as possible
In order to make the training exercises against a FIAC threat more realistic, it is desirable to bring the high speed targets in close proximity to the participating vessel during training without incurring too high of a risk that the vessel will be damaged.